With the increased interest in application of Li aluminosilicate materials as solid electrolytes, this study focuses on investigating the influence of structure on conductivity properties in single-crystal LiAlSi 2 O 6 which is characterized by three crystal polymorphs where only structural arrangements differ while the amount of mobile carriers is identical. Two single-crystal polymorphic phases produced at ambient pressure are with tetragonal P 4 1 2 1 2 symmetry and hexagonal P 6 2 22 symmetry, also referred to as β - and γ -spodumene in the older literature. For this study, flux-grown hexagonal spodumene single-crystals were measured for conductivity parallel to the crystallographic c -axis and the results were compared with previously published results for tetragonal spodumene, both as single-crystal and polycrystalline aggregate, monoclinic spodumene ( α -spodumene) and LiAlSi 2 O 6 glass. The activation energy E a of 79.69 ± 0.38 kJ/mol for hexagonal phase is very similar to the other crystalline polymorphs with the same orientation. However, the σ DC in hexagonal spodumene was determined to be higher than other crystalline phases and about 1.5 orders of magnitude lower than the conductivity in glass LiAlSi 2 O 6 phase. Additionally, the densities of atomic packing were compared between phases, and the differences in the openness of the structures indicate that the more dominant effect on the Li mobility lies with the actual spatial arrangement of Li sites and the Si/Al sublattice.